“A wasted day, again at Le Mans,” was Cal Crutchlow’s verdict on the first day of practice at the French circuit. He had a point: the first session of practice started wet but dried out towards the end, though the track was never really fully dry.

FP2 started completely wet, with plenty of rain, but again the rain stopped and the track improved a little. At no time did the track ever really become consistently one thing or another. And with dry weather forecast for Saturday and Sunday, there was not much to learn.

“It’s just a joke,” Crutchlow complained. “I don’t know why we come here again at this time of the year. First of all, obviously I really believe we should have a race in France, I like coming to France, the fans are completely mad and I have a good rapport with them.

But I don’t know why we come here and I don’t know why we come here now. No idea. Every year, I can’t tell you a year I’ve raced in MotoGP where it’s been sunny all weekend, I don’t think.”

Naturally, this kicked off a heated debate among the various nationalities of journalists over whose country has the worst weather, with Silverstone and Assen the candidates giving Le Mans a proper run for their money. Crutchlow remained firm.

“I love Le Mans, the history is superb, bike racing at Le Mans is massive as well as car racing. But the circuit’s no good. It’s stop-start and the time of the year’s always raining.” It isn’t ‘always’ raining at Le Mans, of course. But it feels like it does.

Every Day’s a School Day

Wet weather made for an unproductive day, for most. But there were exceptions. “I always learn, every time I go on the bike,” Maverick Viñales said. The Movistar Yamaha rider struggled in the wet initially in MotoGP, but has made big steps in recent races.

The Yamaha is a strong package in the wet, and Viñales used the wet session to get more time on rain tires, and to work on the electronics. “We sacrificed some laps on the dry tires to make some more laps on the rain tires and I was feeling really great,” he said.

He had more trouble in the afternoon, when there was more water on the track, but he was inside the top ten in both sessions, and sure of passage to Q2 whatever the weather.

The same could not be said for both factory Ducatis. Andrea Dovizioso spent his time working on a set up which could be useful on Saturday in the dry. Jorge Lorenzo spent more time working on adapting to the Michelin wets.

He admitted he had struggled in mixed conditions on the Yamaha last year. “It’s true that I have maybe too many bad experiences in 50-50 conditions with slicks,” he said. I had big crashes, crashes that I got injured. I take much more time than most of the riders to be aggressive and to push in the corners.”

The problem with doing that is the tires just don’t get up to temperature quickly enough in the rain. “If you don’t warm up the tire, you won’t have the speed, and the risk of a crash is even more.”

At the end of the session, Lorenzo had put new tires again and suffered the same problem, a lack of confidence in getting the tire up to temperature quickly. But Lorenzo viewed it as a learning experience, a chance to improve. It was also a chance to get some setup data in the wet, something he also lacked with the Ducati.

Tire Talk

Tires were very much the subject of discussion outside the track as well. At the meeting of the Safety Commission, the riders discussed the results of the vote on which front tire construction to use for the rest of the season.

The vast majority – 20 riders to 3, with just Jorge Lorenzo, Maverick Viñales, and Loris Baz voting against switching back to the stiffer construction tire first trialled at Valencia last year.

To understand the decision, first a little explanation. Last year, the front Michelin slick had a different profile and a different, stiffer construction. At Valencia last year, Michelin introduced a different profile, to provide a little more edge grip and better feel on the edge of the tire. Michelin gave this construction the code ’70’.

This ‘locking’ is where the front was oscillating between locking up and rolling again very quickly while braking. To solve this problem, Michelin introduced a softer construction with the same profile, which retained the edge grip and eliminated this ‘locking’. This tire was given the code ’06’.

The Code Enigma

Do not ask me to explain the codes Michelin uses. The French tire manufacturer refuses to divulge the codes to journalists, for fear of creating confusion when journalists who half understand the system try and fail to explain it to inattentive readers.

That fear is not entirely unfounded, but Michelin’s use of codes has always been enigmatic, even going back to the period when there were still tire wars. Crew chiefs and mechanics from that period still complain to this day of the seemingly incomprehensible naming conventions which tires were given. But I digress.

The ’06’ may have been better while braking in a straight line, but the tire had more of a tendency to move while braking into the corner, giving riders who trail braked deep into corners a lack of confidence in the front end.

That movement produced other problems as well: with the rubber moving on the carcass, the temperature in the tire was rising, causing the front to overheat. Riders, especially those on Hondas who relied on braking, were having to risk choosing a harder compound in search of stability, risking a lack of grip, especially in the early laps of a race.

During testing, the riders had almost all expressed a preference for the ’06’, preferring the fact that it fixed the locking problem. Valentino Rossi had been adamant that the ’70’ was better, but he had little support.

That all changed at the first race in Qatar: once racing started, riders were pushing the tires harder, and running into problems. They were also doing twenty-plus laps at a stretch, rather than just four or five.

Foiled by Customs

In the space between Qatar and Argentina, Michelin attempted to bring tires with the ’70’ construction to the track, albeit using a soft compound of rubber.

A strike meant they got held up at customs, and it proved not to be possible to get them to the circuit on time for everyone to test them. Instead, the decision was made that the riders would all test them at the test on the Monday after Jerez, and then take a vote.

Speaking to the riders that Monday evening, there were a lot of weasel words as riders refused to reveal their hands.

Opinion seemed fairly well split, and the agreement had been than if 60% of the riders preferred the ’70’, then Michelin would drop the ’06’ construction and switch. In the period between Jerez and Le Mans, opinion shifted, with the overwhelming majority deciding for the ’70’.

Most, but not all, however. At a private test to prepare for Mugello, Jorge Lorenzo and Andrea Dovizioso both tried the ’70’ while they worked on getting a setup for what is the biggest race of the year for Ducati.

There, Lorenzo decided he wanted to keep the ’06’, and tried to persuade Michelin to bring both constructions of front tire. Lorenzo’s cause was lost at Le Mans, when the vote went 20-3 against him.

70 vs. 06

Of course, there is more to it than that. Marc Márquez went into great detail on Friday evening. When he tested the two tires at Jerez, he had not felt a major difference.

“I didn’t feel like day and night difference,” he said. “They don’t feel like two completely different tires, but I feel slightly better with the ’70’, which is the old casing.”

Complicating the issue was the fact that Michelin had changed compounds as well as construction, Márquez explained.

“Another thing that nobody considered is that this year, they didn’t only change the casing, but also they changed the rubber. The rubber is different, they have different names for the rubber types. If they start to consider many things, they must also consider this.”

Changing compounds changes the feel of the tires, the stiffness of the tire and how it responds.

Márquez disagreed with Lorenzo’s premise that having two different construction tires would be fairer. After all, if Michelin had to bring two different constructions to each race, developing the two equally would be almost impossible, as each would have different requirements.

“To have two casings is so difficult for Michelin,” he said, “especially to understand which one is better, which one we want more, because Michelin is still working to improve the tires. And then in which casing they will improve, on the ’06’ or ’70’? I mean, for one group of riders, or the other group?”

It would be fairer to choose a single construction, a single direction, and try to improve that for everyone.

Five Laps Ain’t Twenty-Five Laps

The problem with the ’06’, Márquez explained, came especially during races. “For some reason, this year many riders complain about the front tire during the race, especially when you follow some bikes, it starts to move so quick, starts to overheat the front tire,” he said.

That meant riders had to change their riding styles, in some cases to such an extent that it was visible on TV. “Sometimes you can see from the TV, we are riding really smooth, because you have to be very careful, especially during the races.”

The strength of the ’70’ was under braking, Márquez explained. “It’s a tire that gives better support in the braking point. You go in with the brakes, and it keeps better the front, it has more stability. And for riders that brake late, or for heavy riders, that can be better. And then on the mid corner, for me it was exactly the same.”

That was very different from the ’06’, he said. “The problem with the other one is that you always have some movement. And then for the practice, to do five laps, then stop, then five laps, it’s not a problem. But during 28 laps, it has this movement, the temperature is going up, and up and up.”

“You start to overheat the tire, and you start to lose rubber, because always you have some movement. And I believe that the ’70’ is better for this, more stability, and especially for the race distance, much more consistent.”

And so from Mugello, the ’06’ construction will be shelved, and the ’70’ construction, or Valencia prototype as it is sometimes referred to, will take its place. Ducati – or rather, Jorge Lorenzo – lost this battle, and Valentino Rossi and Marc Márquez won the day.

Lessons from History

Will it make much difference? In reality, tire development never stops. It is reminiscent of the time in 2014 when Bridgestone applied a heat-resistant layer to the carcass of its rear tires, to prevent problems of overheating it had encountered a couple of years earlier.

Jorge Lorenzo suffered badly at the start of that season, as the heat-resistant layer meant he had less grip right on the edge of the tire, which he exploited to the full.

Yet after four or five races, Bridgestone modified their compound selection to make the edge a little softer, and therefore give a bit more feel at high lean angles. By the end of the year, Lorenzo was back on course and completely comfortable with the tires.

It is likely that Michelin will follow a similar course. Motorcycle tires are as dynamic as the vehicles they are fitted to, and so a change to the construction automatically has a knock on effect on the choice of compounds.

So far this year, Michelin has been selecting compounds based on data from last year compared with the data collected during testing and the races held so far. Once the grid switches to tires using the ’70’ construction, that data will go into improving compound selection for future races.

In the short term, this will help the Hondas and Valentino Rossi, the riders who brake late and brake deep into the corners, while robbing riders who love corner speed of their ability to feel the edge of the tire at high lean angles.

In the long term, Michelin will find better compound compromises which retain both braking stability and better feel from the tire.

While Jorge Lorenzo has been the most vociferous critic of the switch to the ’70’, it is potentially Maverick Viñales who has the most to lose. Lorenzo is in his first year with Ducati, and is not expected to win the title this season.

Viñales, however, has spent the entire off season working towards this, the opportunity to seize his first world championship. How he adapts will be a measure of his flexibility.

Photo: Ducati Corse

This article was originally published on MotoMatters, and is republished here on Asphalt & Rubber with permission by the author.